


Firsts

by ShadowsSmutHouse (ShadowoftheLamp)



Series: AIP Tallest AU [1]
Category: Invader Zim
Genre: Alien Biology, Alien Sex, First Time, M/M, Mild Cum Inflation, Oral Sex, Plot What Plot/Porn Without Plot, Tallest Zim AU
Language: English
Status: Completed
Published: 2021-01-22
Updated: 2021-01-22
Packaged: 2021-03-13 23:01:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,033
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28911267
Author URL: https://archiveofourown.org/users/ShadowoftheLamp/pseuds/ShadowsSmutHouse
Summary: Dib shows Zim what a kiss is and things escalate very, very rapidly.
Relationships: Dib/Zim (Invader Zim)
Series: AIP Tallest AU [1]
Series URL: https://archiveofourown.org/series/2120442
Comments: 2
Kudos: 82





	Firsts

**Author's Note:**

> Heyyy it's meeeee. I briefly considered either A: Slapping this on my alt account or B: Making an entirely new one, buuuuut a lot of my porn is specifically for my aus, so people would probably catch on. However, I don't want to clutter up my main with a buncha old porn (this one's from November '19) so I just made a pseud for it since I want to put my twitter backlog somewhere. I'll probably be uploading stuff over the next couple of weeks. 
> 
> Edit: Apparently if you hit shadowofthelamp as the account and not the pseud you see this from there. Huh. Well, it’s warned for.
> 
> Yes, this is the AIP Tallest au, so yes, there _are _a couple brief mentions of mpreg, but I figured it wasn't really worth tagging for people who are _looking_ for mpreg since it's just those mentions. __
> 
> Anyway, this is just porn so enjoy. I figured I'd tag PWP because while the _au_ has a plot this oneshot doesn't.

“You’ve never kissed anyone?” Dib raised an eyebrow, and Zim folded his legs. His long, long, legs. Dib wasn’t sure he’d seen legs that long on anyone before, except maybe in the mirror. Zim's were nicer though.

“Should I have?” Zim’s left antenna was lowered, but the right one bounced slightly as his eyes narrowed.

“I just- I always kind of figured most leaders sort of slept around with whoever they wanted.” Dib shrugged. The silk of the bedsheets was a relief on his scars, compared to the scratchy, threadbare ones in his ship. Right now, he was clad only in a pair of boxers, and Zim was in what appeared to be a spandex bodysuit. Or rather, whatever the alien equivalent of spandex was. “How old are you again?”

“A hundred eighty, why?”

"Oh, right, I forgot irkens live really stupidly long.” Dib scooted a little closer, settling himself directly on Zim’s lap. “I’ll show you what a kiss is.”

“Dib-” Zim started before Dib grabbed his cheeks with both hands, squishing them in before pulling Zim’s head towards his own and smashing their lips together.

It was messy- Zim froze for a few seconds, but leaned in, setting his claws on Dib’s side. They dug into the skin when Dib opened his mouth slightly and began sucking on Zim’s lip. The pleased hums that were thrumming from Zim’s chest made Dib throw his leg out and settle it back down over Zim’s side so their chests and stomachs were pressed together.

Dib’s head bobbed slightly as he adjusted again, one hand trailing up to tweak the base of Zim’s antennae. It got an actual _squeak_ out of Zim, and he pulled back to grin.

“Did you just-”

Zim grabbed the back of his head, smashing their faces together again and practically attacking Dib’s mouth. His tongue ran over Dib’s lips, lingering on the scar on the lower one before poking the insides of his cheeks. Dib could feel his cheeks burning, and he ground down on Zim’s crotch, fisting the material on Zim’s shoulders as his mouth was fucked with a tongue a good three times the size of his own.

Just as Zim was about to push down his throat, Dib pulled back at a sensation beneath him, a line of drool breaking from their tongues and sliding down his chin. Zim growled.

“You said you’d show me.” 

“You’re a fast learner. The hell is that?” He slid off Zim’s lap, setting his palm flat against Zim’s crotch, and heard the material stretch as Zim’s toes curled. 

“Oooh…”

“It feels flat.” Dib let his fingers roam, looking for a seam in the bodysuit. “Do you have a zipper on this or something?”

“I don’t need to take it off, most of the time. It cleans... when I do.” Zim’s tongue was poking past his lips as Dib explored his body before he jolted up. “Gah! What did you _do_ to me, you sweat-creature?”

“Me? I didn’t do anything besides kiss you!” A grin spread across Dib’s face. “You _really_ don’t know what this is, do you?”

“It feels- wet,” Zim admitted. “Am I bleeding? Did you-”

“No, I didn’t cut you. You’re aroused.” Dib spotted a tiny seam on Zim’s shoulder and reached for it. A quick tug and the material fell open, exposing Zim’s chest. It was completely smooth, not a scar or blemish marring the perfect green skin. No nipples either, although Dib hadn’t really expected any. Zim tried to yank it back up, but Dib grabbed the edge, pulling it down more.

“You dare-”

“I’m going to _help_ you, you moron.” Dib snapped. “Butt up, I’m taking this stupid suit off so we can do this properly. I’m already half-naked, you might as well be _all_ naked.” 

Zim ground his ass against the bed so Dib couldn't remove the suit. “No.”

“You want me to get you off through it? It’s just going to make a big mess.”

“Someone else can clean it up.”

Dib rolled his eyes. “I’m sure that will go over well. Leader of the irken empire, found copulating with some random weirdo of a species no one knows. Everyone applauds him for somehow losing his virginity to dirty space bounty hunter _after_ he has their child.”

“What’s vaginity?”

Dib snorted out a laugh. “It’s the idea of having sex for the first time.”

“Have you?”

“What?”

“Have you had a sex?”

Dib stared at Zim, who was leaning forward, the upper half of the bodysuit pooling in his lap. “Yeah, I popped that one years ago. Being a lonely, horny teen in space kind of will do that.”

"Is that something you do with someone else?"

"It can be, or it can be something you do by yourself. I've done both."

“Who was it?” Zim’s fingers curled up- his approximation of a fist, and Dib ran a hand through his hair, grimacing at the grime buildup. Man, he needed to wipe down. 

“Somebody? I tried not to get names, I wasn’t looking for anything long term. I had a galaxy to save, people will just weigh you down. I’m still figuring out how the hell I ended up here, to be honest.” He shrugged. “Anyway, most of them were years ago. I haven’t landed an irken yet, though, none have ever been interested. But if _you_ have no idea, maybe you’re just all really, really repressed.” Dib reached for the suit again, and this time, Zim wiggled a little to allow him to slide it down, past his legs. He wasn’t wearing any kind of undergarment, and Dib stared, one hand settled on each of Zim’s thighs.

There was a long slit, a darker green than the skin surrounding it. It was puffy on the edges and soaked with translucent pink slick. It smelled sweet, like every kind of candy mixed into a cocktail. Dib bent forward without thinking, running his tongue up it, and Zim keened, one leg hooking over Dib’s back and driving his nose directly into the top of the slit. The smell was even stronger this close, as was the taste- it was exactly as sweet as its scent, and Dib lapped at it. Whatever it was, Zim was making a _lot_ of it. 

Some deep part of him wondered if Dib’s blood was enough to knock Zim up, then if Zim’s slick could work in reverse, but the rest of him promptly told it to go fuck itself, although somehow it left by way of his very, very hard cock. He’d barely noticed it before, too focused on Zim, but now he reached back to palm himself, sliding a hand sticky with Zim down his boxers.

He was about to start pumping when something brushed his nose. He lifted his head as a lined point began to rise from the slit. “Holy- what the _fuck?_ ”

“What did you do?” Zim shrieked, kicking Dib in the shoulder and knocking him back on his ass.

“ _Me?_ I was just eating you out, how was I supposed to know you’ve got some kind of tentacle shit going on?” They both watched as more and more of the thick pink- well, maybe not a tentacle, but it was sort of like a flexible cone, straining upwards and swaying from side to side. “So you can give birth _and_ you’ve got a dick?”

“Shut up!” Zim’s hand hovered over the thing, before brushing it with the tips of his fingers and shuddering. “O-oh…”

Dib watched the flush on Zim’s cheeks deepen before crawling back over. He waited until Zim’s eyes were squeezed shut when he began stroking himself before gripping the base. Zim twitched but didn’t try to claw his face off, so Dib’s fingers dipped into the premade pink liquid to lube the length up. He began to stroke up and down, and Zim moaned, setting one hand on Dib’s shoulder and the other on the top of his head. 

“D-dib…”

“Geez, I can’t believe you’re five times my age and you’ve never jacked off before,” Dib said. “This thing is the size of my forearm, how does it even _fit_ inside of you? You’re doing me next, got it?”

“Mmm…” Zim clearly wasn’t listening to a word he said, legs twitching. Out of curiosity, Dib lowered his lips to the tip, tasting the precum. It was almost sickly saccharine, sweeter than whatever fluid had been coming out before. He’d need to get a sample to figure out-

His thoughts were thoroughly cut off when it thrust deeper into his mouth. He was about to spit it out, but Zim’s claws digging into his shoulders were his only warming before a _geyser_ erupted, shooting hot cum directly down his throat. Zim’s hand on his skull kept him down, and he was forced to swallow. And swallow. And swallow. Jesus, how much did irkens even _cum?_

Finally, Zim released him, although Dib noticed when still looking down that it had been enough to slightly bloat out his starved frame. A swipe at his face revealed some had dribbled down his chin to stick in the wiry hair in his patchy beard. “A little warning would have been nice, you know!” 

“ _That’s_ kissing?” Zim’s eyes practically glittered in the soft light, and Dib couldn’t help some of the anger melting away.

“No, that’s sex. Kissing was just our lips pressing together, we went fast.” He slid his boxers off. “Now, if you excuse me, I’m going to finish it before- woah!”

Zim pinned him down, prodding at his cock. “Mine’s bigger.”

“Hey, my size is fine for a human!” Dib protested, and Zim laughed.

“For a _human_.” He considered for a moment. “What was it you were doing?”

“Oral, but-” Dib gripped the sheets as Zim’s tongue wrapped _around_ his length. He bucked up, and Zim swallowed half of it with ease- did he not have _any_ gag reflex at all?

“That’s- wow, you _are_ a fast learner,” Dib managed to stammer out. He watched Zim past the slight curve of his stomach, happy trail an arrow leading directly to the irken sucking his cock like it was a lollipop. Zim pulled back just before Dib felt his orgasm burst, splattering white over his face.

Zim hissed, swiping at his face before grabbing part of the sheets and wiping frantically to try and get it off. Dib snickered, but it was wheezy as he tried to regain his breath.

“That’s what you get for using me as a cum dump, space boy. A facial.”

Zim shot him a glare, but the flush on his cheeks and the sticky semen right where the bridge of his nose would be dampened the effect. 

“I could have you executed for-”

“For what? You should be thanking me. If you got Twix from blood, you’d probably get twins from cum if you'd swallowed.” He tugged his boxers back on. “Besides, you got even.” He set a hand on his stomach. “Whoof, that’s weird.” It probably wouldn’t be noticeable once he pulled his shirt back on, but he’d be feeling it all day.

“Where are you going?” Zim demanded.

“Back to the ship,” Dib said, but Zim grabbed him, tugging him down on the bed.

“Oh no you don't. I _require_ you to stay with me. It’s the least you can do after ruining my bedsheets.”

Dib scanned the bed. “It looks like you did most of the damage. Like ninety percent of it's pink.”

“Lies!”

“Buuuuuut if you’re into cuddling, as long as you don’t decapitate me in my sleep…” Dib trailed off with a yawn. “A little can’t hurt.” He had a chip that warned him of imminent danger while he slept. Sure, it gave false positives about 85% of the time and woke him up on more occasions than he could count, but at least he wasn’t dead yet, so he figured it had been a good buy.

He waited until Zim’s breathing evened out to allow himself to drift off, glancing over to make sure the door was still locked.

He never felt Zim set a possessive hand on his hip and pull him close.

**Author's Note:**

> Comments and kudos appreciated! Like I said, this one's old, but I do still like it.


End file.
